scholarly journals Optical Coherence Tomography: Basic Concepts and Applications in Neuroscience Research

2017 ◽  
Vol 2017 ◽  
pp. 1-20 ◽  
Author(s):  
Mobin Ibne Mokbul
Keyword(s):  
Optical Coherence Tomography ◽  
Imaging Modality ◽  
Biomedical Science ◽  
Optical Coherence ◽  
Label Free ◽  
Cross Sectional ◽  
Imaging Tool ◽  
Neuroscience Research ◽  
Challenges And Opportunities ◽  
Review Study

Optical coherence tomography is a micrometer-scale imaging modality that permits label-free, cross-sectional imaging of biological tissue microstructure using tissue backscattering properties. After its invention in the 1990s, OCT is now being widely used in several branches of neuroscience as well as other fields of biomedical science. This review study reports an overview of OCT’s applications in several branches or subbranches of neuroscience such as neuroimaging, neurology, neurosurgery, neuropathology, and neuroembryology. This study has briefly summarized the recent applications of OCT in neuroscience research, including a comparison, and provides a discussion of the remaining challenges and opportunities in addition to future directions. The chief aim of the review study is to draw the attention of a broad neuroscience community in order to maximize the applications of OCT in other branches of neuroscience too, and the study may also serve as a benchmark for future OCT-based neuroscience research. Despite some limitations, OCT proves to be a useful imaging tool in both basic and clinical neuroscience research.

scholarly journals Modern Trends in Imaging V: Optical Coherence Tomography for Rapid Tissue Screening and Directed Histological Sectioning

2012 ◽  
Vol 35 (3) ◽  
pp. 129-143 ◽  
Author(s):  
Woonggyu Jung ◽  
Stephen A. Boppart
Keyword(s):  
Optical Coherence Tomography ◽  
Real Time ◽  
Image Guidance ◽  
Diagnostic Yield ◽  
Imaging Modality ◽  
Imaging Techniques ◽  
Optical Coherence ◽  
Sampling Errors ◽  
Cross Sectional

In pathology, histological examination of the “gold standard” to diagnose various diseases. It has contributed significantly toward identifying the abnormalities in tissues and cells, but has inherent drawbacks when used for fast and accurate diagnosis. These limitations include the lack ofin vivoobservation in real time and sampling errors due to limited number and area coverage of tissue sections. Its diagnostic yield also varies depending on the ability of the physician and the effectiveness of any image guidance technique that may be used for tissue screening during excisional biopsy. In order to overcome these current limitations of histology-based diagnostics, there are significant needs for either complementary or alternative imaging techniques which perform non-destructive, high resolution, and rapid tissue screening. Optical coherence tomography (OCT) is an emerging imaging modality which allows real-time cross-sectional imaging with high resolutions that approach those of histology. OCT could be a very promising technique which has the potential to be used as an adjunct to histological tissue observation when it is not practical to take specimens for histological processing, when large areas of tissue need investigating, or when rapid microscopic imaging is needed. This review will describe the use of OCT as an image guidance tool for fast tissue screening and directed histological tissue sectioning in pathology.

scholarly journals Role of Optical Coherence Tomography on Corneal Surface Laser Ablation

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Bruna V. Ventura ◽  
Haroldo V. Moraes ◽  
Newton Kara-Junior ◽  
Marcony R. Santhiago
Keyword(s):  
Optical Coherence Tomography ◽  
Laser Ablation ◽  
Imaging Modality ◽  
Corneal Thickness ◽  
Optical Coherence ◽  
Corneal Surface ◽  
Cross Sectional ◽  
Surface Laser ◽  
The Time Domain

This paper focuses on reviewing the roles of optical coherence tomography (OCT) on corneal surface laser ablation procedures. OCT is an optical imaging modality that uses low-coherence interferometry to provide noninvasive cross-sectional imaging of tissue microstructurein vivo.There are two types of OCTs, each with transverse and axial spatial resolutions of a few micrometers: the time-domain and the fourier-domain OCTs. Both have been increasingly used by refractive surgeons and have specific advantages. Which of the current imaging instruments is a better choice depends on the specific application. In laserin situkeratomileusis (LASIK) and in excimer laser phototherapeutic keratectomy (PTK), OCT can be used to assess corneal characteristics and guide treatment decisions. OCT accurately measures central corneal thickness, evaluates the regularity of LASIK flaps, and quantifies flap and residual stromal bed thickness. When evaluating the ablation depth accuracy by subtracting preoperative from postoperative measurements, OCT pachymetry correlates well with laser ablation settings. In addition, OCT can be used to provide precise information on the morphology and depth of corneal pathologic abnormalities, such as corneal degenerations, dystrophies, and opacities, correlating with histopathologic findings.

scholarly journals The Value of Anterior Segment Optical Coherence Tomography in Different Types of Corneal Infections: An Update

2021 ◽  
Vol 10 (13) ◽  
pp. 2841
Author(s):  
Ahmed A. Abdelghany ◽  
Francesco D’Oria ◽  
Jorge Alio Del Barrio ◽  
Jorge L. Alio
Keyword(s):  
Optical Coherence Tomography ◽  
Imaging Modality ◽  
Wide Spectrum ◽  
Anterior Segment ◽  
Corneal Edema ◽  
Response To Treatment ◽  
Optical Coherence ◽  
Slit Lamp ◽  
Cross Sectional

Anterior segment optical coherence tomography (AS-OCT) is a modality that uses low-coherence interferometry to visualize and assess anterior segment ocular features, offering several advantages of being a sterile and noncontact modality that generates high-resolution cross-sectional images of the tissues. The qualitative and quantitative information provided by AS-OCT may be extremely useful for the clinician in the assessment of a wide spectrum of corneal infections, guiding in the management and follow-up of these patients. In clinical practice, infections are routinely evaluated with slit-lamp biomicroscopy, an examination and imaging modality that is limited by the physical characteristics of light. As a consequence, the depth of pathology and the eventually associated corneal edema cannot be accurately measured with the slit-lamp. Therefore, it represents a limit for the clinician, as in vivo information about corneal diseases and the response to treatment is limited. Resolution of corneal infection is characterized by an early reduction in corneal edema, followed by a later reduction in infiltration: both parameters can be routinely measured with standardized serial images by AS-OCT.

scholarly journals Choroidal Vascularity Index: An In-Depth Analysis of This Novel Optical Coherence Tomography Parameter

2020 ◽  
Vol 9 (2) ◽  
pp. 595 ◽  
Author(s):  
Claudio Iovino ◽  
Marco Pellegrini ◽  
Federico Bernabei ◽  
Enrico Borrelli ◽  
Riccardo Sacconi ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Vascular System ◽  
Imaging Modality ◽  
Optical Coherence ◽  
Optic Nerve Diseases ◽  
Imaging Tool ◽  
Depth Analysis ◽  
Potential Applications ◽  
Choroidal Vasculature ◽  
Public Domain Software

Remarkable improvements in optical coherence tomography (OCT) technology have resulted in highly sophisticated, noninvasive machines allowing detailed and advanced morphological evaluation of all retinal and choroidal layers. Postproduction semiautomated imaging analysis with dedicated public-domain software allows precise quantitative analysis of binarized OCT images. In this regard, the choroidal vascularity index (CVI) is emerging as a new imaging tool for the measurement and analysis of the choroidal vascular system by quantifying both luminal and stromal choroidal components. Numerous reports have been published so far regarding CVI and its potential applications in healthy eyes as well as in the evaluation and management of several chorioretinal diseases. Current literature suggests that CVI has a lesser variability and is influenced by fewer physiologic factors as compared to choroidal thickness. It can be considered a relatively stable parameter for evaluating the changes in the choroidal vasculature. In this review, the principles and the applications of this advanced imaging modality for studying and understanding the contributing role of choroid in retinal and optic nerve diseases are discussed. Potential advances that may allow the widespread adoption of this tool in the routine clinical practice are also presented.

scholarly journals Development Of Dynamic Light Scattering Optical Coherence Tomography Methods For Detecting Cell Death

2021 ◽  
Author(s):  
Nico Joseph John Arezza
Keyword(s):  
Cell Death ◽  
Optical Coherence Tomography ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Exponential Decay ◽  
Morphological Changes ◽  
Imaging Modality ◽  
Optical Coherence ◽  
Cross Sectional ◽  
Single Exponential

Dynamic light scattering (DLS) techniques can provide information about the quantity, size, and motion of light scatterers within a volume based on temporal fluctuations in its light scattering profile. In DLS, autocorrelation functions (ACFs) are computed from light intensity vs time signals acquired from optical imaging setups. A parameter known as the decorrelation time is computed from each ACF and is inversely related to the average motion speed of scatterers within the imaging volume. Optical coherence tomography is an imaging modality that generates 2D cross-sectional images based on light backscattered from a sample, and the combination of DLS with OCT is known as dynamic light scattering optical coherence tomography (DLS-OCT). Previously, DLS-OCT has been used to detect apoptosis, a form of programmed cell death, in non-adherent leukemia cells. Cells undergoing apoptosis experience predictable morphological changes that results in an increase in intracellular motion, and therefore a decrease in decorrelation time. We applied DLS-OCT methods to quantify the decorrelation times in adherent breast cancer cell pellets that were either untreated, treated with 20 ng/mL paclitaxel for 24 or 48 hours, or deprived of media for 24 or 48 hours. The mean decorrelation times in the paclitaxel-treated and nutrient deprived groups were significantly lower than in the untreated cells (p<0.05), suggestive of increased intracellular motion due to morphological cellular changes associated with cell death. We also investigated a new model to fit to ACFs generated by DLS-OCT of cell pellets. Typically, ACFs are fit to single exponential decay curves. We developed a model that expresses the ACFs from in vitro experiments as a sum of multiple exponential decay curves using an algorithm known as CONTIN. The curves produced by CONTIN fitted the experimental data much better than the single exponential decay fits. We speculate that the CONTIN fits, each of which resembled a superposition of three exponential decay functions, may result from light scattered from three different types of scatterers within cells, such as lysosomes, mitochondria, and nuclei.

scholarly journals Feature definition and comprehensive analysis on the robust identification of intraretinal cystoid regions using optical coherence tomography images

2021 ◽  
Author(s):  
Joaquim de Moura ◽  
Plácido L. Vidal ◽  
Jorge Novo ◽  
José Rouco ◽  
Manuel G. Penedo ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Medical Imaging ◽  
Imaging Modality ◽  
Developed Countries ◽  
Point Of View ◽  
Machine Learning Techniques ◽  
Optical Coherence ◽  
Cross Sectional ◽  
Factors Affecting ◽  
Invasive Techniques

AbstractCurrently, optical coherence tomography is one of the most used medical imaging modalities, offering cross-sectional representations of the studied tissues. This image modality is specially relevant for the analysis of the retina, since it is the internal part of the human body that allows an almost direct examination without invasive techniques. One of the most representative cases of use of this medical imaging modality is for the identification and characterization of intraretinal fluid accumulations, critical for the diagnosis of one of the main causes of blindness in developed countries: the Diabetic Macular Edema. The study of these fluid accumulations is particularly interesting, both from the point of view of pattern recognition and from the different branches of health sciences. As these fluid accumulations are intermingled with retinal tissues, they present numerous variants according to their severity, and change their appearance depending on the configuration of the device; they are a perfect subject for an in-depth research, as they are considered to be a problem without a strict solution. In this work, we propose a comprehensive and detailed analysis of the patterns that characterize them. We employed a pool of 11 different texture and intensity feature families (giving a total of 510 markers) which we have analyzed using three different feature selection strategies and seven complementary classification algorithms. By doing so, we have been able to narrow down and explain the factors affecting this kind of accumulations and tissue lesions by means of machine learning techniques with a pipeline specially designed for this purpose.

scholarly journals Development Of Dynamic Light Scattering Optical Coherence Tomography Methods For Detecting Cell Death

2021 ◽  
Author(s):  
Nico Joseph John Arezza
Keyword(s):  
Cell Death ◽  
Optical Coherence Tomography ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Exponential Decay ◽  
Morphological Changes ◽  
Imaging Modality ◽  
Optical Coherence ◽  
Cross Sectional ◽  
Single Exponential

Dynamic light scattering (DLS) techniques can provide information about the quantity, size, and motion of light scatterers within a volume based on temporal fluctuations in its light scattering profile. In DLS, autocorrelation functions (ACFs) are computed from light intensity vs time signals acquired from optical imaging setups. A parameter known as the decorrelation time is computed from each ACF and is inversely related to the average motion speed of scatterers within the imaging volume. Optical coherence tomography is an imaging modality that generates 2D cross-sectional images based on light backscattered from a sample, and the combination of DLS with OCT is known as dynamic light scattering optical coherence tomography (DLS-OCT). Previously, DLS-OCT has been used to detect apoptosis, a form of programmed cell death, in non-adherent leukemia cells. Cells undergoing apoptosis experience predictable morphological changes that results in an increase in intracellular motion, and therefore a decrease in decorrelation time. We applied DLS-OCT methods to quantify the decorrelation times in adherent breast cancer cell pellets that were either untreated, treated with 20 ng/mL paclitaxel for 24 or 48 hours, or deprived of media for 24 or 48 hours. The mean decorrelation times in the paclitaxel-treated and nutrient deprived groups were significantly lower than in the untreated cells (p<0.05), suggestive of increased intracellular motion due to morphological cellular changes associated with cell death. We also investigated a new model to fit to ACFs generated by DLS-OCT of cell pellets. Typically, ACFs are fit to single exponential decay curves. We developed a model that expresses the ACFs from in vitro experiments as a sum of multiple exponential decay curves using an algorithm known as CONTIN. The curves produced by CONTIN fitted the experimental data much better than the single exponential decay fits. We speculate that the CONTIN fits, each of which resembled a superposition of three exponential decay functions, may result from light scattered from three different types of scatterers within cells, such as lysosomes, mitochondria, and nuclei.

scholarly journals Feasibility evaluation of micro-optical coherence tomography (μOCT) for rapid brain tumor type and grade discriminations: μOCT images versus pathology

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Xiaojun Yu ◽  
Chi Hu ◽  
Wenfei Zhang ◽  
Jie Zhou ◽  
Qianshan Ding ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Diagnostic Imaging ◽  
Brain Neoplasm ◽  
Ex Vivo ◽  
Diagnostic Tools ◽  
Tumor Type ◽  
Optical Coherence ◽  
Cross Sectional ◽  
Imaging Tool ◽  
Imaging Results

Abstract Background Precise identification, discrimination and assessment of central nervous system (CNS) tumors is of critical importance to brain neoplasm treatment. Due to the complexity and limited resolutions of the existing diagnostic tools, however, it is difficult to identify the tumors and their boundaries precisely in clinical practice, and thus, the conventional way of brain neoplasm treatment relies mainly on the experiences of neurosurgeons to make resection decisions in the surgery process. The purpose of this study is to explore the potential of Micro-optical coherence tomography (μOCT) as an intraoperative diagnostic imaging tool for identifying and discriminating glioma and meningioma with their microstructure imaging ex vivo, which thus may help neurosurgeons to perform precise surgery with low costs and reduced burdens. Methods Fresh glioma and meningioma samples were resected from patients, and then slices of such samples were excised and imaged instantly ex vivo with a lab-built μOCT, which achieves a spatial resolution of ~ 2.0 μm (μm). The acquired optical coherence tomography (OCT) images were pathologically evaluated and compared to their corresponding histology for both tumor type and tumor grade discriminations in different cases. Results By using the lab-built μOCT, both the cross-sectional and en face images of glioma and meningioma were acquired ex vivo. Based upon the morphology results, both the glioma and meningioma types as well as the glioma grades were assessed and discriminated. Comparisons between OCT imaging results and histology showed that typical tissue microstructures of glioma and meningioma could be clearly identified and confirmed the type and grade discriminations with satisfactory accuracy. Conclusions μOCT could provide high-resolution three-dimensional (3D) imaging of the glioma and meningioma tissue microstructures rapidly ex vivo. μOCT imaging results could help discriminate both tumor types and grades, which illustrates the potential of μOCT as an intraoperative diagnostic imaging tool to help neurosurgeons perform their surgery precisely in tumor treatment process.

scholarly journals Longitudinal Monitoring of Flow-Diverting Stent Tissue Coverage After Implant in a Bifurcation Model Using Neurovascular High-Frequency Optical Coherence Tomography

Neurosurgery ◽  
2020 ◽  
Author(s):  
Jildaz Caroff ◽  
Robert M King ◽  
Giovanni J Ughi ◽  
Miklos Marosfoi ◽  
Erin T Langan ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
High Frequency ◽  
Imaging Modality ◽  
Rabbit Model ◽  
Flow Diverter ◽  
Tissue Growth ◽  
Data Sets ◽  
Optical Coherence ◽  
Cross Sectional

Abstract BACKGROUND Tissue growth over covered branches is a leading cause of delayed thrombotic complications after flow-diverter stenting (FDS). Due to insufficient resolution, no imaging modality is clinically available to monitor this phenomenon. OBJECTIVE To evaluate high-frequency optical coherence tomography (HF-OCT), a novel intravascular imaging modality designed for the cerebrovascular anatomy with a resolution approaching 10 microns, to monitor tissue growth over FDS in an arterial bifurcation model. METHODS FDS were deployed in a rabbit model (n = 6), covering the aortic bifurcation. The animals were divided in different groups, receiving dual antiplatelet therapy (DAPT) (n = 4), aspirin only (n = 1), and no treatment (n = 1). HF-OCT data were obtained in vivo at 3 different time points in each animal. For each cross-sectional image, metal and tissue coverage of the jailed ostium was quantified. Scanning electron microscopy images of harvested arteries were subsequently obtained. RESULTS Good quality HF-OCT data sets were successfully acquired at implant and follow-up. A median value of 41 (range 21-55) cross-sectional images were analyzed per ostium for each time point. Between 0 and 30 d after implant, HF-OCT analysis showed a significantly higher ostium coverage when DAPT was not given. After 30 d, similar growth rates were found in the DAPT and in the aspirin group. At 60 d, a coverage of 90% was reached in all groups. CONCLUSION HF-OCT enables an accurate visualization of tissue growth over time on FDS struts. The use of FDS in bifurcation locations may induce a drastic reduction of the jailed-branch ostium area.

Feasibility and Clinical Utility of Ultra-Widefield–Navigated Swept-Source Optical Coherence Tomography Imaging

2021 ◽  
pp. 247412642199733
Author(s):  
Kyle D. Kovacs ◽  
M. Abdallah Mahrous ◽  
Luis Gonzalez ◽  
Benjamin E. Botsford ◽  
Tamara L. Lenis ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Clinical Utility ◽  
Clinical Decision Making ◽  
Imaging System ◽  
Imaging Modality ◽  
Case Series ◽  
Subretinal Fluid ◽  
Optical Coherence ◽  
Swept Source ◽  
Oct Imaging

Purpose: This work aims to evaluate the clinical utility and feasibility of a novel scanning laser ophthalmoscope-based navigated ultra-widefield swept-source optical coherence tomography (UWF SS-OCT) imaging system. Methods: A retrospective, single-center, consecutive case series evaluated patients between September 2019 and October 2020 with UWF SS-OCT (modified Optos P200TxE, Optos PLC) as part of routine retinal care. The logistics of image acquisition, interpretability of images captured, nature of the peripheral abnormality, and clinical utility in management decisions were recorded. Results: Eighty-two eyes from 72 patients were included. Patients were aged 59.4 ± 17.1 years (range, 8-87 years). During imaging, 4.4 series of images were obtained in 4.1 minutes, with 86.4% of the image series deemed to be diagnostic of the peripheral pathology on blinded image review. The most common pathologic findings were chorioretinal scars (18 eyes). In 31 (38%) eyes, these images were meaningful in supporting clinical decision-making with definitive findings. Diagnoses imaged included retinal detachment combined with retinoschisis, retinal hole with overlying vitreous traction and subretinal fluid, vitreous inflammation overlying a peripheral scar, Coats disease, and peripheral retinal traction in sickle cell retinopathy. Conclusions: Navigated UWF SS-OCT imaging was clinically practical and provided high-quality characterization of peripheral retinal lesions for all eyes. Images directly contributed to management plans, including laser, injection or surgical treatment, for a clinically meaningful set of patients (38%). Future studies are needed to further assess the value of this imaging modality and its role in diagnosing, monitoring, and treating peripheral lesions.

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